<?php

/**
 * Des 加密解密
 * Class FDes
 */
class FDes {
    var $key;

    function FDes($key) {
        $this->key = $key;
    }

    function encrypt($input) {
        $size = mcrypt_get_block_size('des', 'ecb');
        $input = $this->pPack($input, $size);
        $key = $this->key;
        $td = mcrypt_module_open('des', '', 'ecb', '');
        $iv = @mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
        @mcrypt_generic_init($td, $key, $iv);
        $data = mcrypt_generic($td, $input);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        $data = base64_encode($data);
        return $data;
    }

    function decrypt($encrypted) {
        $encrypted = base64_decode($encrypted);
        $key = $this->key;
        $td = mcrypt_module_open('des', '', 'ecb', '');
        //使用MCRYPT_DES算法,cbc模式
        $iv = @mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
        $ks = mcrypt_enc_get_key_size($td);
        @mcrypt_generic_init($td, $key, $iv);
        //初始处理
        $decrypted = mdecrypt_generic($td, $encrypted);
        //解密
        mcrypt_generic_deinit($td);
        //结束
        mcrypt_module_close($td);
        $y = $this->pUnPack($decrypted);
        return $y;
    }

    function pPack($text, $blockSize) {
        $pad = $blockSize - (strlen($text) % $blockSize);
        return $text . str_repeat(chr($pad), $pad);
    }

    function pUnPack($text) {
        $pad = ord($text{strlen($text) - 1});
        if ($pad > strlen($text))
            return false;
        if (strspn($text, chr($pad), strlen($text) - $pad) != $pad)
            return false;
        return substr($text, 0, -1 * $pad);
    }
}